Methods are known in the art for glass manufacturing wherein glass-forming, batch ingredients are compacted into agglomerates and then are dried and heated in a chamber by a direct contact with flue gases from a glass melting furnace so as to produce free-flowing agglomerates which are then conveyed and discharged to the glass melting furnace. These agglomerates are composite, integral, self-supporting masses consisting essentially of all the substantial batch materials and may take the form of balls, extrusions, discs, briquettes, and pellets. The agglomerates are discharged to a vertical bed contained within a chamber and furnace flue gases pass, in direct contact with and countercurrently to, downwardly moving pellets of the bed to preheat them.
One method known in the art to form the agglomerates is to combine the glass forming batch ingredients with a liquid such as caustic or water. In the context of drying and heating water-containing, glass batch agglomerates with flue gases from a fossil fuel fired melting furnace, the most conventional process equipment of the prior art is a shaft type heater, or chamber, i.e., a vertical bed of substantial height, and preferably a bed in which the agglomerates flow downwardly through the chamber and in which the flue gases flow countercurrent to the agglomerates, to substantially continuously, in a single processing operation, dry and preheat them.
This drying and preheating of agglomerates at times may generate high particulate emissions in the flue gases exhausting from the chamber. Observations indicate that the primary source of this high dust load in the preheat hopper effluent is the result of agglomerate spalling, particularly in the upper portion of the agglomerate bed. Wet agglomerate spalling is defined as a loss of agglomerate integrity during the drying process.